Turnstile antenna



Jan. 4 1944. N. w. ARAM TURNSTILE ANTENNA Filed July 2. 1942 2 Sheets-Shet 1 N. w. ARAM TURNSTILE ANTENNA Filed JuI Ly 2. 1942 2 Sheets-Sheet 2 pose of clarity;

Patented Jan. 4 1944 UNITED STATES PATENT OFFICE"- 2,s:a,sc4'

Nathan W. Aram, Chicago, IlL, assignor to Zenith Radio Corporation, Chicago, 111., a cori oration of Illinois Application .luly 2, 1942, Serial No. 449,431

'rcl. 250-33) 34 Claims.

feed lines are properly matched by the radiating elements.

A further object of the invention'is to pro- I vide a practical turnstile antenna in which the power is equally divided between the radiating elements at various levels.

A further object of the invention is to provide a practical turnstile 'antenna in which the feeding of a multiplicity of radiating elements in proper phase is effected without twisting or spiraling feed-lines around the mast.

,A further object of the invention is to pro- .vide a turnstile antenna which can be installed without difficult and tedious impedance matching adjustments during installation.

A further object of the invention is to pro- 4 vide a practical turnstile antenna in which many of the phasing elements and connections of the feeder system may be placed below the level of the mast and inside a building.

Other objects, advantages and capabilities will appear from the following description of a ,pre-' ferred embodiment thereof taken in 'conjunction with the accompanying drawin n which:v

Figure 1 is a perspective view of animproved turnstile antenna embodying my invention;

Fig. 2 is an expanded diagrammatic view showing the dipole elements of the turnstile antenna shown in Fig. 1 and the feeder system including the phasing and impedance matching elements thereof, the outer conductor being omitted from some of the co-axial lines for the puring the manner in which any vertical coaxial line of the antenna is connected to any dipole element of the uppermost two bays.

Referring to the drawings, my improved turnstile antenna is preferably mounted upon a metal mast III which is grounded. Since the ,fleld strength existing at any given receiving point is proportional. to the height ofthe transmitting antenna, the mast Ill is preferably at the highest position available. This is normally on the top of one of the highest buildings in a city.

The radiating elements of myimproved'antenna are folded dipoles. Folded dipoles consist of a plurality of parallel, close-spaced conductors connected togetherin series. A common form of folded dipole comprises a conductor of approximately half a wave length, two return bends at the ends thereof, and two portions which extend inwardly therefrom to points of termination adjacent the center of the major length of the dipole. The center of this major length of the dipole-is a voltage zero and may be grounded. Consequently, in my antenna this major length is in two parts each of which is conductively secured to diametrically opposed points on the mast ll.

Furthermore, in this common form of folded dipole the return bends are oppositely directed so that the two minor portions are normally located on one side of the major portion. My improved antenna embodies a type of dipole in which the return bends are in the same direction, that is, both clockwise or both counterclockwise, so that the minor portions of the dipole lie on opposite sides'of the major portion of the dipole. As will hereinafter appear,

' Fig. 3 is a sectional plan view taken on the line 3-3 of Fig. 1 showing the lowermost level of the turnstile antenna in plan view;

Fig. 4 is a similar plan view taken on the line 4-4 of Fig. 1 showing the dipoles of the second level from the bottom in plan view;

Fig. 5 is asectional detail showing thezmanner in which any vertical coaxial line of the antenna is connected to any dipole element on the bays other than the uppermost two bays; and

F18. 6 is a similar sectional detail view showthis modification facilitates the connecton oi the feeder system to' the dipoles. v

. A turnstile antenna may comprise a plurality of bays or levels mounted on the mast and having a spacing of half a wave length. Each level or bay normally comprises two dipoles at right angles to each other. All the dipoles in one panel, that is, the dipoles having one direction,

for example, north and south in one case, and east and west in the other case, are excited in phase, and the dipoles of one direction, north and south, for example, are excited out of phase by ninety degrees from the dipoles of the other direction, east and west, for instance. With this ninety-degree relationship, the radiation pattern is substantially circular. Radiation is concentrated towards the horizontal direction as a function of the number of levels with radiating elements in the same phase.

For convenience of reference, I will refer to the various dipoles as N2-S2, W3-E3, etc., these indicia meaning the second dipole from the bottom lying in the north and south direction and the third dipole from the bottom lying in the west and east direction. Similarly, I find it convenient to refer to the individual radiating elements as N2, E3, SI, etc. It is to be noted, however, that this nomenclature is for ease of reference only. Since the radiated pattern is substantially circulanthe points of the compass to which the dipoles are directed have no effect and it is to be understood that the antenna as a whole can be considered to be rotated from its positlon through any number of degrees without any change of effect.

, I have previously pointed out that each of my dipoles has return bends directed in the same direction. I prefer to make this direction the same at any one bay or level and to alternate the direction for each bay or level along the mast.

Thus, referring to Fig. 3, which shows in plan the dipole elements of the lowermost bay or level, it is to be noted that the return bends are in the counterclockwise direction, whereas in Fig. 4 which is a corresponding view of the second bay or level, the return bends are in the clockwise direction. Indeed, all the odd numbered bays, counting from the bottom, follow the pattern of Fig. 3, and all the even numbered bays, counting from the bottom, follow the pattern of Fig. 4. It will therefore be understood that the free ends of the radiating elements Ni, N3, etc., are in vertical alignment, so that they ma be fed by a feeder line II which extends upwardly along the mast III. This feeder line is located between the N and W elements, being more adjacent the N elements. The N2, N4, etc., elements have their free ends between the N and E elements and nearer the N elements, and they are arranged to be fed by a line I2.

The W2, W4 elements are fed by a line l3, the WI, W3 elements, etc., being fed by a line It. The SI, S3 elements are fed by a line I5, the S2, S4, etc., elements being fed by a line I6. The E2, E4 elements are fed by a line H, the El, E3 elements, etc., being fed by a line I8.

By reference to Fig. 3 or 4, it will be seen that the feeder lines constitute a circumferential series around the mast III in the following order: II, I2, I3, I1, I5, I6, l4 and I3. It is to be noted'th'at II and I2 are adjacent the N elements on opposite sides thereof, that IT and I8 are adjacent the E elements and on opposite sides thereof, that I5 and I6 are adjacent the S elements and on opposite sides thereof, and that I 3 and I4 are adjacent the W elements and on opposite sides thereof. This enables all these feeder lines to extend vertically upwards along the mast I0 and without any crossing of feeder lines.

Since each of these feeder lines is connected to alternate dipoles in the longitudinal direction of the mast, and since these alternate dipoles are one wave length apart, each feeder line, in the embodimentof the invention illustrated, feeds two dipoles in phase. All circuit elements for correct phasing and impedance matching other than elements being connected to the inner conductor of the coaxial lines through dielectric bushings II in suitable fittings 23 and 20' (Figs. 5 and 6).

The lines II and ii are connected tothe lines 12 and I6, respectively, at points 2l and 22, at a position below the dipole elements and preferably below the mast III.

In order that all the NS dipoles should be excited in phase, the distances of any two N-S dipoles from the points of connection 2| and 22 must either be equal or different from each other by an integral number of wave lengths. This may readily be attained as shown in Fig. 2 by making the lengths of the coaxial lines between NI-SI and N2-S2 and the points of the connections 2| and 22 equal. Since NISI and N2-S2 are at different elevations, the correct distances between them and the common points 2], 22 canconveniently be attained by providing loopsinthe lines II and I5.

In order that all the WE dipoles may be in phase, the coaxial lines I3 and I1 and the coaxial lines 14 and I8, respectively, are connected together at points 23 and 2!, respectively. The points 2|, 22, 23 and 24 are preferably at the same level. Here again, in order that all the WE dipoles may be in phase, the distances from all of the W-E dipoles to the points 23 and 24 should be equal or should differ from each other by an integral number of wave lengths. This may be attained as shown in Fig. 2 by making the length of the coaxial lines between W2--E2 and the points 23 and 2i, the same length as the coaxial lines between Wl-EI and the points 23 and 24.

it has previously been pointed out that there should be a phase difference of 90 between the dipoles of the two different directions. This may be accomplished by using a quarter wave connecting line 25 between point 2| and point 23 and a quarter wave connecting line 26 between point 22 and point24. It should be understood that these quarter wave lines may be transposed so relation between the N-S panel and the E--W panel. This reversal of connection merely reverses the direction of rotation of the field surrounding the antenna. Correct phase relationship between the two panels can be attained by employing coaxial connecting lines 25 and 26 between the points 2| and 22, and 23 and 24, of

three-quarters of a wave length, or indeed any other odd number of quarters of wavelengths. In practice, it is preferred to make these connecting lines one quarter of a wave length.

Energy is supplied to the points 2I and 22 by means of coaxial lines 21 and 28 which convey signal from the transmitter. The lines 21 and 28 are connected to the points 2| and 22 by means of quarter wave length coaxial line transformers 29 and-30, which are connected directly to the points 2| and 22. The quarter wave lengths 29 and 30 have a surge impedance, determined by the ratio of the outer diameter of the inside conductor and the inner diameter of the outside conductor, which is the geometric mean of the surge impedance of the lines 21 and 28 and the parallel impedance of all radiating elements measured at' the points 2I and 22. Thus, the'impedance of the radiating system is prefectly matched to the (impedance of the lines 21 and 28. Normally, I

prefer to keep the outer conductor of the quarter simply varying the. external diameter of the inner conductors of the quarter wave sections 2! and II. It is known that the surge impedance of a coaxial line is the inner conductor, respectively. Consequently, it will readily be understood that by varying d2 of the quarter wave sections 29 and 30, perfect impedance matching can be attained.

It should be noted that a major advantage of this invention is that the circuit permits not only perfect impedance matching between the lines' 2'| and 28 and the feed points 2| and 22. but also provides perfect impedance matching between the vertical lines on the mast and the radiator elements taken in pairs. This can best be understood by tracing the impedance relations through the circuit of the embodiment of the invention just described.- For example, the terminal impedances of .the individual dipoles are chosen to be 280 ohms. Thus, at Nl-Sl, the impedance across the two lines i2 and i8 is 280 ohms. This impedance, viewed at the terminal points of N2- 82, one wave length away, is also 280 ohms. This impedance, in parallel with the 280 'ohm impedance of N2-S2, provides an impedance of 140 ohms between the lines i2 and It at the points of connection with N2-S2. Since equal resistive The coaxial lines l2 and "are, for this embodiment, standard IO-ohm transmission lines which exactly'match the l40-ohm impedance appeering across the connecting-points of 112-82 and they can extend down tothe points 2| and 22 for any practical length so that these points and the quarter wave transformers 29 and 3| may power exists between the dipoles Wl-El and WI-EI, and the dipoles WI-EI and Wl-Ei and the points 22 and 26. v

The relationship between the other pair of 2| and 22 is one fourth of 280 ohms, or 70 ohms; likewise, the net impedance at the points 23 and 24 is "10 ohms. Il-which connect the polnts-2i and22 to 23 and 24 have a surge impedance of '10 ohms so that they are properly terminated at the points 23 and 2.. Each of the lines 25 and has a surge impedance of 35 ohms. Therefore, at the feed points 2!, 22, equal "Ill-ohm impedances are parallel, and equal power division exists between. allthe dipoles.

A folded dipole can very readily-be made with a terminal impedance of 280 ohms. Consequently, I am able to employ as my vertical lines, standard coaxial lines having an impedance of'lil ohms and to obtain, in the manner described above, equal distribution of power among all the dipoles. Furthermore, all the phasing and matching connections other than those inherent in the lines thanselvescanbelocatedbelowthemastandat rltwilhofcourlabethatldonot intendtohelimitedioaantennahaving fmirlevdsorhays. Icanhaveanyothernumber assets;

The quarter wave lines and of levels with suitable adjustment of the terminal 1 impedances of the dipoles employed and/or the surge impedance ofthe vertical lines. Thus, if I desire to increase the number of bays to six, I may employ dipoles having impedances of 420 ohms and! --may connect them inthrees with standard 'lil-ohm coaxial lines in the same manner as the dipoles are connected in pairs in the embodiment of the invention described above.

In the embodiment of the invention described in detail above, there is a slight mismatch between the IO-ohm coaxial lines ii and ii, for example between the points of connection Ni-Sl and N3-S3. This slight mismatching may be cor- 15 rected by employing coaxial lines, between the points of connection of the dipoles thereto, of appropriate surge impedance perfectly to match the impedance of the upper dipole. Thus, in the embodiment specifically described in connection 20 with Fig. 2, I may make-the coaxial lines between Nl-Sl and Nl-SS of lallohms surge impedance so-that they precisely match the impedance of 280 ohms of the Ill-S3 dipole. Similarly, the corresponding portions of the coaxial lines i2 and 5 l8, l2 and I1, and II and it could be 140. ohms. With this modiflcation, all the dipole impedances are perfectly matched and. there are no standing waves on any part of the feeder system. In case more than four bays are embodied in the antenna, it isobvious that the same result may be obtained by using for the vertical feeder lines II, it, etc., coaxial lines having appropriate difierent surge impedances in the portions between the dipoles at which these lines are connected.

quency modulation transmission and they transmission of television and similar signals.

It is to be noted that all the outer conductors 40 of the coaxial lines are grounded and consequently the outer conductors of the coaxial lines II to It extending along'the mast II, are anv chored directly to the mast, for example by cleats. One simple method of securing them may be by means of metal straps it which extend arolmd these conductors, the straps being tight enough to hold the coaxial lines up against the outside of the mast, particularly adjacent the radiating elements effectively to ar und the outer conductors to themast at these points.

My improved antenna is ordinarily employed with the mast vertical and for convenience of description, an antenna with a vertical mast has been described herein, It isto be noted, how.- ever, that for certain purposes the mast and the antenna as a whole may be tilted out of'the vertical direction. Thus, I may locate the mast and the antenna as a whole in a horizontal direction in which'case I will radiate energy principally in an elongated zone. Thus, with a horizontal mast directed east and west, I will have substantially no radiation in the east and west direction and strong radiation in the north and south direction and in directions close thereto. The radiation in this case will, of course, be directed also in an upward direction and in generally upward directions;

Although the invention has been described in connection with specific details of a preferred Iclaim. 1. In a turnstile antenna, in combination. a

My improved antenna is broadly resonant and f is therefore well adapted for the purposes of fret thereof, it must be understood that pair of crossed folded dipoles at each of a plurality of spaced planes, each folded dipole comprising a major length, two return bends and W inwardly directed lesser lengths, all return bends of one plane being directed in the clockwise di-' each plane being directed in the same direction and all bends at successive planes being directed in alternating clockwise and counterclockwise directions, and a plurality of straight feeder lines a connected to said lesser lengths, each feeder line being connected only to corresponding lesser lengths of alternate planes.

3. In an antenna, in combination, a plurality of dipoles at a plurality of planes and located approximately half a wave length apart in the longitudlnal direction and located in a longitudinal panel, and a feeder system comprising two straight feeder lines connected to similar points of one set of alternate dipoles of said panel and another pair of straight feeder lines connected to similar points of the other alternate dipoles of said panel.

4. A turnstile antenna having a pair of crossed dipoles at each of a plurality of spaced planes, the dipoles being directed so as to provide four sets of radial radiating elements directed in four different directions, said dipoles comprising a major length, return bends at the ends thereof, and lesser lengths extending inwardly from said return bends, all return bends at the ends of the radial radiating elements of each plane being in one direction, said direction beingalternately clockwise and counterclockwise along the series of planes.

5. A turnstile antenna having a pair of crossed dipoles at each of a. plurality of spaced planes, the dipoles being directed so as to provide four sets of radial radiating elements directed in four different directions, said dipoles comprising a major length, return bends at the ends thereof, and lesser lengths extending inwardly from said return bends, all return bends at the ends of the radial radiating elements of each plane being in one direction, said direction being alternately clockwise and counterclockwise along the series of planes, and a pair of straight feeder lines for each set of elements directed in one direction, one of said feeder lines being connected to the innermost ends of the lesser portions of alternate radiating elements of one setand the other feeder line being connected to the other alternate elements of said set.

6. A turnstlle antenna comprising a mast, dipoles in crossed relation at a plurality of spaced planes on said mast and located approximately half a wave length apart in the longitudinal direction and providing four aligned series of radial radiating elements directed in four different directions from the mast, a straight feeder system comprising a feeder line connected only to one set of alternate elements of one series and another -feeder line connected only to the other alternate set of said elements of said series, said feeder lines being connected together in such man'ner that the distances of any two elements of said series from the point of connection of said feeder lines are equal or differ by an integral assasos number of wave lengths whereby all of said radiating elementsare excited in phase.

'7. A turnstfle antenna comprising a mast, dipoles in crossed relation at a plurality of spaced planes on said mast and located approximately half a wave length apart in the longitudinal direction and providing four series of radial radiating elements directed in four different directions from the mast, a feeder system comprising four pairs of straight feeder lines, one pair being associated with a series of radial radiating elements, one of said pair being connected only to one set of alternate elements of said series and the other feeder line of said pair being connected only to the other alternate set of said elements of said series, the feeder lines of each pair being connected together in such manner that the distances of any two elements of one series from the point of connection between its associated feeder lines is equal or differs by an integral number of wave lengths, whereby all of said radiating elements of each series are excited in phase.

8. A turnstile antenna comprising a panel of dipoles in parallel longitudinally spaced relation, 9. second similar panel having its dipoles at right angles to the dipoles of the first said panel, each panel comprising a plurality of sets of dipoles spaced from each other by one wave length, and a plurality of straight feeder lines, eatcsh line being connected only to one of said se r 9. A tumstile antenna comprising a panel of dipoles in parallel longitudinally spaced relation, a second similar panel having its dipoles at right angles to the dipoles of the first said panel, each panel comprising a plurality of sets of dipoles spaced from each other by one wave length, a plurality of straight feeder lines, each line being connected only to one of said sets, and phasing connections between said feeder lines below said dipole elements.

10. A tumstile antenna comprising a panel of dipoles in parallel longitudinally spaced relation, a second similar panel having its dipoles at right angles to the dipoles of the first said panel, each set comprising a plurality of dipoles spaced from each other by one-half wave length, and a plurality of straight feeder lines, each line being connected only to a plurality of similar points on dipoles separated from each other by one wave length.

11. A tumstile antenna comprising a panel of dipoles in parallel longitudinally spaced relation, a second similar panel having its dipoles at right angles to the dipoles of the first said panel, the dipoles of each panel being spaced one from the other by one-half wave length, four straight feeder lines, each feeder line being connected only to the alternate dipoles of one panel, each pair of feeder lines of each panel being connected together to excite the dipoles of each panel in phase, a main feeder line connected to one of the points of connection, and a feeder line of an odd number of quarter wave lengths connecting said points of connection whereby said panels are excited in phase quadrature.

12. In a turnstile antenna, in combination, a plurality of dipoles in crossed relation at a plurality of planes and located approximately half a wave length apart in the longitudinal direction and providing four longitudinal series of radial radiating elements directed in four different directions, and a feeder system comprising a straight feeder line connected only to similar points of one set of alternate'elements of one series and another straight feeder line connected to similar points of the other alternate elements of said series, said feeder lines being coaxial lines,

the inner conductor thereof being connected to the'dipoles. a

13. .A turnstile antenna having a pair of crossed dipoles each at a plurality of spaced planes, the

dipoles being directed so as to provide four sets of two elements of said series :romthepoint of radial radiating elements directed in fourq nately clockwise and counterclockwise at succes-' sive planes along the series of planes, and a pair of straight feeder lines for each series of elements directed in onedirection, one of said feeder lines being connected only'to the innermost ends of the lesser portions of one alternate set of radiating elements of one series and the other feeder line being connected only to the other alternate set of said series, said feeder lines being constituted by. coaxial lines the inner conductors whereof are connected to the dipoles.

14. Aturnstile antenna having a pair of crossed dipoles each at a plurality of spaced planes arranged intwo longitudinal panels, the dipoles being directed so as to provide four sets of radial radiating elements directed in four different directions, said dipoles comprising a major length, return bends at the ends thereof,. and lesser lengths extending inwardly from said return bends, all return bends at the ends of the of connection between its two feeder lines are equal or differ by an integral number of wave lengths whereby all or said radiating elements are excited in phase.

16. A turnstile antenna comprising a mast,

dipoles in crossed relationship at a plurality of spaced planes on said mast and located approximately half a wave length apart in the longitudinal direction and providing four longitudinal series of radial radiating elements directed in four different directions from the mast, a feeder system comprising four pairs of straight coaxial feeder lines, one pair being associated with a longitudinal series of radial radiating elements, one of said pair being connected only to one set of alternate elements ofsaid series and the other radial radiating elements being directed in one direction at each plane, said direct on being alternately clockwise and counterclockwise along the series of planes, a pair of straight feeder lines for each series of elements directed in one direction, one of each pair of feeder lines being connected only to the innermost ends of the lesser portions of one alternate set of radiating elements of one'series and the other feeder line of said pair being connected only to the other alternate set of said series, said feeder lines being constituted by coaxial lines the inner conductors. whereof are connected to the dipoles, the feeder lines of each pair being connected together at .points of connection to supply their elements in phase,'main feeder coaxial lines excited in O posite phase connected to the points of connection of one panel, and coaxial lines of an odd number of quarter wavelengths connecting the points of connection of one panel to the points oi connection'of the other panel, whereby all thedipoles of each panel are excited inphase and all the dipoles of the two panelsare excited in phase quadrature. V

15'. A turnstile antenna comprising, a vmast;

dipoles in crossed relationship at a plurality of feeder line of said pair being connected only to the other alternate set of said elements of said series.,each pair of said coaxial feeder lines beingconnected together in such manner that the distances of any two elements of one series from the 1'7. A turnstile antenna comprising a. panel of,

dipoles in parallel longitudinally spaced relation, a second similar panel having its dipoles at right angles to the dipoles of the iirst said panel. each panel comprising a plurality of sets of dipoles spaced from each other by one wave length, and a plurality of straight coaxial "feeder lines, the inner conductor of each line being connected only to one of said sets.

18. A turnstile antenna comprising a panel of dipoles in parallel longitudinally spaced relation, a second similar panel having its dipoles at right angles to the dipoles of the first said panel, each panel comprising a plurality of dipoles spaced from each other by one-half wave length,'and

a plurality of straight coaxial feeder lines, each line being connected only to a plurality of similar points on dipoles separated from each other by one wave length.

19. A turnstile antenna comprising a panel of angles to the dipoles 0f the first said panel, each panel comprising a plurality of dipoles spaced from each other by one-half wave length. a pinraiity of straight coaxial feeder lines, each line being connectedonly to a plurality of similar points on dipoles separated from each other by one wave l t a-pair of main coaxial feeder lines. a feeder connecting system connecting the straight coaxial feeder lines for similarends of one panel and similar ends of another panel to one main feeder line, another feeder connecting system connecting thestraiglit coaxial feeder lines for the other ends of both said panels tothe other main coaxial feeder line, said feeder connecting systems comprising coaxial lines .of

such length to feed opposite ends of said dipoles with 180 phase difference, to feed all dipoles of each panel in phase. and to feedone panel with v a phase of ahead of the other panel.

20. A turnstile antenna comprising a panel of 'Q' dipoles in parallel longitudinally spaced relation,- a second similar panel having its-dipoles at right angles to the dipoles of the first said paneli rthe dipoles of each panel being spacedonefrom the other by one-hair wave length. eight straight nectedtogetherinsuchmanner thatthedistances u feeder lines, each feeder line connectedonl to similar ena of alternate dipoles of one panel,

gather to excite the dipoles of the panel in phase, a pair of main feeder lines excited in opposite phase, connected to the points of connection of thefeederlinesofonepanehandfeederlinesof mlytoalignedendsofthedipolesandtheinner conductor of the other line being connected only to the other aligned ends of the dipoles, the surge impedancesofthelinesbeingarrangedtomatch the parallel impedances of the dipoles.

22. In a turnstile antenna, in combination, a plurality of folded dipoles in spaced and aligned relation, the spacing being one wave len and a pair of straig t coaxial feeder lines the inner eondnctorofonelinebeingconnectedonlyto aligned ends of the dipoles and the inner condnctoroftheotherlinebelngconnectedonlyto theotheraligned endsdfthedlpolesthesurge impedances of the lines below the dipoles being arrangedtomatchtheparallelofthe dipoles, and the surge impedances of the portlonsof the lines between two dipoles being arranged to match the parallel impedances of the dipoles above said portions.

23. In a turnstile antenna, in combination, a plurality of folded dipoles arranged in crossed relation in two longitudinal panels, the dipoles eing spaced apart half a wave length plurality of coaxial feeder lines, each feeder line having its innerconductor connectedonlytosimilarends of alternate dipoles of a panel, each pair of coaxial feeder lines thus connected to similar ends of the dipoles of a panel being connected together at points of connection to feed said similar ends in phase, a pair of main feeder coanal lines of D- posite phase connected to the points of connection of one panel and coaxial lines of an odd num er of quarter wave lengths connecting the poinm of connection of one panel to the points of connection of the other panel, the surge impedances of the first said feeder lines connected to one alternate set of dipoles of one panel being arranged to match the parallel impedances of the dlpola to which they are connected.

24. In a turnstile antenna, in combination, a plurality of folded dipoles arranged in crossed relation in two longitudinal panels, the dipoles beingspacedaparthalfawavelen h. aplur ii y of coaxial feeder lines, each feeder line having its inner conductor connected only to similar ends of alternate dipoles of a panel, each pmr ofcoaxialfeederlinesthusconnectedtosimilar ends of the dipoles of a panel being connected together at pdnm of connection to feed said simflarendsinphmapairofmainfeedercoaxial lines of opposite phme connected to the points of connectlonofonepanelandcoaxiallinesofan odd number of quarter wave lengths connecting the points of connection of one panel to the points of connection of the other panel, the surge impedances of the first said lines connected to one alternate set of dipoles of one panel being arodd number of quarter wave lengths connect-,

ranged belowlast said dlpolestomatch the parallel impedances of last said dipoles, and the surge impedances of last said lines between ad jacent last said dipoles beingarrangcd to match the parallel impedances of those of last said'dipoles above said portions.

25, In a turnstile antenna, in combination, a plurality of folded dipoles arranged in crossed relation in two longitudinal panels, the dipoles being spaced apart half a wave length. a plurality of coaxial feeder lines, each feeder line having its inner conductor connected only to similar ends of alternate dipoles of a panel, each pairof coaxial feeder lines thus connected to similar ends of the dipoles of a panel being connected together at points of connection to feed said similar ends in phase, a pair of quarter wave length transformers connected to the points of connection of one panel, a pair of main feeder coaxial lines connected to said transformers, and coaxial lines of an odd number of quarter wave lengths connecting the points of connection of one panel to the points of connection of the other panel, the surge impedances of the coaxial lines of an odd to one alternate set of dipoles of one panel being arranged to match the parallel impedances of the dipoles to which they are connected, the surge impedances of the coaxial lines of an old number of quarter wave lengths being arranged to match the parallel impedances of the two panels, and the impedances of the quarter wave length coaxial line transformers being arranged tomatchtheimpedancesofthemainfeedercoaxial lines to the parallel impedances across the connecting points to which they are connected.

26. In a tumstile antenna, in combination, a plurality of folded dipoles arranged in crossed relation in two longitudinal panels, the dipoles being spaced apart half a wave len a plurality of coaxial feeder lines, each feeder line having its inner conductor connected only to similar ends of alternate dipoles of a panel, each pair of coaxial feeder lines thus connected to similar ends of the dipoles of a panel being connected together at points of connection to feed said similar ends in phase, a pair of quarter wave length transformers connected to the points of connection of one panel, a pair of main feeder coaxial lines connected to said transformers, and coaxial Iins of an odd number of. quarter wave lengths connecting the points of connection of one panel to the points of connection of the other panel,

the surge impedances of the first said lines connected to one alternate set of dipoles of one panel being arranged below last said dipoles to match the parallel impedances of last said dipoles, and the surge impedances of last said lines between adjacent last said dipo es being arranged to match the parallel impedances of those of last said dipoles above said portions, the surge impedancesofthecoaxiallinesofanoddnnmber of quarter wave lengths being arranged to match the parallel impedances of the two panels, and the impedances of the quarter wave length coaxial line transformers being arranged to match the impedances of the main feeder coaxial lines to the parallel impedances acros the connectin: points to which they are connected.

27. A feeder system comprising eight coaxial lines, two of said coaxial lines being connected to separate points of connection, and two others of said coaxial lines being connected to another two separate points of connection, a pair of coaxial lines of an odd number of half wave lengths connectingtwoothersofsaideightlinestoflrstsald assasea points of connection. another pair of coaxial lines of an odd number of half wave lengths connecting the other two of said eight lines to the 1 other two points of connection, and a pair of coaxial lines of an odd number ofquarter wave lengths connecting the two pairs of separate points of connection.

28. A feeder system comprising eight coaxial lines, two of said coaxial lines being connected to two separate points of connection, and two others of said coaxial lines being connected to another two separate points of connection, a pair of half wave length coaxial lines connecting two others of said eight lines to first said points of connection, another pair of half wave length coaxial lines connecting the other two of said eight lines to the other two points of connection, and a pair of quarter wave length coaxial lines connecting the two pairs of separate points of connection.

29. A feeder system comprising eight coaxial lines, two of said coaxial lines being connected to separate points of connection, and two others -of said coaxial lines being connected to another two separate points of connection, a pair of co axial lines of an odd number of half wave lengths connecting two others of said eight lines to, first said points of connection, another pair of oolast said coaxial lines being arranged to. match the impedances at said connecting points, a pair of main coaxial feeder lines excited in opposite phase, and a pair of quarter wave coaxial line 7 transformers connecting said main lines too.

axial lines of an odd number of half wave lengths connecting the other two of said eight lines to the other two points of connection, and a pair of coaxial lines of an odd number of quarter wave lengths connecting the two pairs of separate points of connection, the surge impedances of last said coaxial hues being arranged to match the impedances at said connecting points.

30. A feeder system comprising eight coaxial lines, two of said coaxial lines being connected to two separate points of connection, and two others of said coaxial lines being connected to another two separate points of connection, a pair of half wave length coaxial lines connecting two others of said eight lines to first said points of connection, another pair of half wave length coaxial lines connecting the other two of said eight lines to the other two points of connection, and a pair of quarter wave length coaxial lines connecting the two pairs of separate points of connection, the surge impedances of last said coaxial lines being arranged to match the impedances at said connecting points.

31. A feeder system comprising eight coaxial lines, two of said coaxial lines being connected to separate points of connection, and two others of said coaxial lines being connected to another two separate points of connection, a pair of coaxial lines of an odd number of half wave lengths pair of said separate points and providing-impedance matching between said lines and said p ints.

32. A feeder system comprising eight coaxial lines, two of said coaxial lines being connected to twoseparate points of connection, and two others of said ,coaxial lines being connected .to another two separate points of connection, a pair of half wave length coaxial lines connecting two others of said eight lines to first said points of connection, another pair of half wave length coaxial lines connecting the other two of said eight lines to the other two points of connection, a pair of quarter wave length coaxial lines connecting the ,two pairs of separate points of connection, the surge impedances of last said coaxial lines being arranged to match the impedances at said connecting points, a pair of main coaxial feeder lines excited in opposite phase, and a pair of quarter wave coaxial line transformers connecting said main lines to a pair of said separate points and providing impedance matching between said lines and said points.

33. In combination, a plurality of parallel folded dipoles, each dipole having a major length, two return bends and two inwardly di-' rected lesser lengths, the return bends of one of said dipoles being directed in one direction around the center of said one dipole and the return bendsof an adjacent dipole being directed in the opposite direction around the center of said other dipole.

34. A turnstile antenna comprising a pinrality of cross' dipoles arranged in two parallel series, a plurality of straight feeder lines connected to said dipoles and a feeder system connected to said straight feeder lines to excite the dipoles of each series in phase and to excite the System.

NATHAN W. ARAM.

cnmrncnn or GOBREOTIOI.

Ieimnt No. 2,338,561;- Janhary 1i, 191m.

NATHAN W. LEAH.

It is hereby eertified. that error appeore in the printed specification ottheebove'mmbered. patent requiring e orreotionae follows: Page 3, tiret 501m; 11m 1 3, for r ulatiomm recid- -re1ettonehip--;- line 52,

strike out the norde""rhe reletioneh iplbetneen theother pair or and insert ineteed rhe'net parallel impedance betneen the p0inta-;' page 1;, first Column, line 67, before "feeder" etrike;qut"'streig1t' and insert the same :after comprising a in line 68; plge 6; eeoond column. line 211,, strike out coaxial-line: or an odd and insert ineteed "first any lines conneoted-'; line 28, for "old' reid---odd--; end that the said Lettors Patent ahouldbe reed with this correction therein that the same may conform to the reeord or the case in the Patent Officer Signed. m sealed this law a of April, A. 1). 191m.

Leslie Frazer (Sell) Acting Commissioner of Patents. 

